7 Things You Need To Know To (Finally!) Start Composting

February 13, 2017

First of all, let’s get this out of the way: You may not know it, but you already compost. The food waste in your garbage, the bits of tissue and cotton and hair in your bathroom trash bin, the bags of leaves you rake and gather every fall—all of that decomposes.

Over the last century, we’ve drawn a delicate curtain—more recently in the form of drawstring plastic trash bags, invented in 1984—between our world and the reality of that decomposition. In some ways, this is a good thing. In 1879, the New Orleans public dump was described as a “festering, rotten mess,” and at the beginning of the twentieth century, New York City was a “nasal disaster, where some streets smell like bad eggs dissolved in ammonia.” Improved sanitation has meant better living and less disease, but in fating all garbage to the trashcan, we do a disservice to the earth. In landfills, biodegradable materials are sealed off from oxygen, causing anaerobic decomposition that produces methane—a lot of it, which in turn drives climate change (landfill waste is responsible for nearly a fifth of domestic methane emissions). In putting all of our waste in the garbage, we also pass up an opportunity to do something easy, completely natural, rewarding, and free: Make soil.

I promise there is nothing hypertechnical about basic composting. I learned how to do it from a farmer whose technique was as simple as pushing all his plant and food waste in a pile with his backend loader and leaving it to sit for a few months. “That becomes soil?” I said with saucer-wide eyes,“Magic!”

“Magic?” He snorted, “No, that’s composting.”

When the season ended, I came home to New York City. I dug a hole in my yard roughly eighteen inches deep and as wide as the shovel’s blade. Down into the bottom foot went our food waste and spent garden plants. My roommate rebelliously contributed fish skins and bones, I added citrus peels, and we capped it off by pouring a flat beer on top of the mess. To keep rodents away, I covered everything with six inches’ worth of shredded newspaper and then closed the pile with a thick layer of soil. It was our hope that from this grave-like aperture life would emerge as loam, ready to apply to our garden. 

Related: How to Choose the Best Compost Bin For You

In the interim, I furthered my education in decomposition by smelling it out. Biking through NYC, I came to recognize the acidic excretions produced by anaerobic bacteria by the hot, nostril-burning smell that wafted from tightly sealed garbage bags full of food waste. I stopped in Central Park to sniff tree stumps sprouting with mushrooms in order to memorize the scent of decay by saprophytic fungi. I lifted up handfuls of dirt from vegetable gardening beds and inhaled to get a sense of the “sweet” smell of healthy, finished soil. That’s what I wanted in my own compost.

Three months went by, and my roommate and I checked in on our buried backyard pile. It took us a few futile digs before we realized that our food waste was gone—it had well and truly become soil. Success had come quietly, steadily, and naturally. As I became familiar with the process, making compost felt like throwing a party. Sure, it was kind of messy around the edges, but with the right atmosphere (temperature and moisture levels) and food (organic material), your guests arrive. Throughout the process of decomposition, the atmosphere changes and various characters join and leave the pile.  The sign of a successful party? Compost happens.

A lot of new composters fret unnecessarily about having the right type of bin or balancing the mysterious ledger of so-called “browns” and “greens.”  But composting isn’t like the chemistry of baking pastry—it’s the inexact science of a good stir-fry. You don’t need as many bells and whistles as you think, just a sense of curiosity and patience. But regardless of the system you use, successful composting maintains a few basic principals:


1. Know what to compost

Many guides will tell you not to add cooked foods, meats, citrus, or manure to your compost pile. Look: Every single organic material decomposes, including those no-nos. However, if you want to be careful about which decomposers you invite to your bin, skip those items. Fats (dairy, oil, cheese), meats (including fish), and manure can be hazardous.  Manure is additionally complicated because it adds salts, anathema to any garden. Uncovered fruit can attract flies (more annoying than harmful). Compost systems (i.e. bins, tumblers, etc.) handle materials differently. No matter the system, you can’t compost plastic. Glass and metal take forever to decompose. But everything else will eventually rot. 

Angela Sevin photography/getty

2. Get to know your guests

Physical decomposers like fly larvae, worms, beetles, mites, and snails grind, chew, and suck on decomposing plant based materials, breaking them down into smaller pieces that microscopic organisms like protozoa, bacteria, and fungi can eat. Don’t worry about inviting them over—most are already present in your organic material or in the area around your compost pile and will be eager to jump in. (Though if you’re composting indoors, you will need to collect some worms.) If you want to get to know these characters better, you can purchase a simple microscope attachment for your phone (I use the ProScope Micro Mobile), which allows you to zoom in and take photos if you’re curious. 


3. Be flexible about “browns” and “greens”

The terms don’t refer to color but to carbon and nitrogen ratios. “Greens” are more nitrogen-rich items, like kitchen scraps, grass clippings, and coffee grounds. Piles heavy in these items don’t need as much supplemental moisture and tend to need more turns with a garden fork to keep them aerated. “Browns” are carbon-rich materials, like dry leaves and cardboard. Good compost requires a mix of the two, but don’t sweat the specifics. Use what you have, and through observation over time, adjust as necessary. 

Image Source/Getty

4. Use your nose

One of the easiest ways to tell if you are adding the right balance of materials is the smell of the pile over time. As compost processes, it should smell hot, funky, and slightly sweet. Typically, a putrid smell is the sign of a pile with too many nitrogen-rich (green) materials. Ease up on the “greens,” and give the pile a turn or two with a garden fork to improve air flow—while you can technically leave your pile completely alone and still get compost, aerating accelerates decomposition. A lack of smell can indicate a stagnant pile; add moisture to restart the party by including more “greens” or wetting the pile with a garden hose. 

Shana Novak/getty

5. Small is beautiful

Even a compost pile’s most visible decomposers are quite small. Chopping your organic material into two- to four-inch pieces increases the surface area available to macro- and microorganisms, hastening decomposition. If you add larger material to your pile, it is more likely to stagnate. No one gets hurt—it just takes longer to break down. 


6. Keep an eye on the temperature

The temperature of your pile tells you who’s at your party and what stage the party’s at. With the exception of vermicomposting systems, there’s a general arc: As new material is added and starts to break down, the temperature will rise. When your pile reaches between 140 and 160 degrees at its center, it’s actively creating compost. It will eventually cool. At 68 degrees, your soil is likely ready to harvest. The easiest way to keep track is with a compost thermometer, a tool like a meat thermometer but with a longer stem.That long stem is necessary to probe the center of the pile, as the temperature closer to the surface will always run cooler. (In winter, you may want to take a couple of extra steps to keep your pile toasty.)


7. Keep the air flowing

As organic materials break down, they release moisture and the pile begins to condense, squeezing out oxygen. Without good air flow, a compost pile becomes dominated by anaerobic bacteria (that trash bag again). You’ll eventually get compost, but it will take a lot longer and just plain stink. To readjust the bacterial population, turn your pile using a garden fork or a tumbler system. It’s smart to turn your pile every two weeks regardless of its smell to continuously fold your materials back into the center of the pile. This reboots the microorganisms feasting in the core. If you don’t turn your pile, composting will just take longer—a year instead of three months, for example.